Because of increasing environmental concerns related to manure disposal, some farms are adopting manure handling systems that diminish the potential environmental problems associated with the large amount of manure produced in relatively small areas. For example, in Wisconsin as of 2007, there were 20 farms with fully operational anaerobic manure digesters with an average of 1,474 cows in each farm (USDA, 2010). Manure liquid-solid separation is another alternative option to manure handling. The separated liquid can be reused in barns as flush water, a crop nutrient source, or irrigation water; whereas, the separated solids can be recycled as bedding, used as nutrient source for crop production, or sold off farm as a horticultural amendment (personal communication with farmers). Manure composting has been used as an alternate manure handling process. Composting decreases the total amount of manure through water loss and also eliminates most of the pathogens in manures (Rynk et al., 1992). In-barn composted bedded packs are an alternative option to complete composting and consist of bedding layers (e.g., saw dust) that are constantly added to the barn floor without removal of the older layer. The bedded pack is aerated daily to stimulate microbial decomposition.
Soil Science Extension
University of Wisconsin Madison